In an effort to train hard and maintain top shape for the Pokémon League, Ash decides to try some surfing. When he hits rough waters, a surfer named Victor comes to the rescue and tells Ash about a gigantic wave called Humungadunga which hits the island just once every 20 years. Having failed to ride the wave in his youth, Victor is afraid to try again so Ash and Pikachu must provide Victor with the confidence he needs to conquer Humungadunga!